Method and apparatus for producing blades



p 8, 1964 w. A. PAILLE ETAL 3,147,539

METHOD AND APPARATUS FOR PRODUCING BLADES Filed Oct. 9, 1958 llSheets-Sheet 1 .srmemv INVENTOR5. 14715500 4. P4/[ Z A q #1 E BY 65 5 4/L Iii 4.04

P 8, 1964 w. A. PAILLE ETAL 3,147,539

METHOD AND APPARATUS FOR PRODUCING BLADES Filed Oct. 9. 1958 11Sheets-Sheet 3 INVENTOR5. Mazda/z m/zzf FER/$46M Fan 15a BY 65% 55 1/ Le 6J4 Sept. 8, 1964 w. A. PAILLE IETAL 3,147,539

METHOD AND APPARATUS FOR PRODUCING BLADES Filed 00;. 9, 1958 llSheets-Sheet 4 f/V 561/ L zwzo Sept. 8, 1964 w. A. PAILLE ETAL METHODAND APPARATUS FOR PRODUCING BLADES Filed Oct. 9, 1958 ll Sheets-Sheet 5Sept. 8, 1964 w. A. PAlLLE ETAL 3,147,539

METHOD AND APPARATUS FOR PRODUCING BLADES Filed 001;. 9. 1958 llSheets-Sheet 6 mvmons #015200 7. P/J/ME 669/166 M Fan/415E BY f/VE 5 1 Lg w. A. PAILLE ETAL 3,147,539

11 Sheets-Sheet 7 Sept. 8, 1964 METHOD AND APPARATUS FOR PRODUCINGBLADES Filed Oct. 9, 1958 mm K p 1964 w. A. PAILLE ETALMETHODANDAPPARATUS FOR PRODUCING BLADES Filed Oct. 9. 1958 11Sheets-Sheet 8 P 8, 1964 w. A. PAILLE ETAL 3,147,539

METHOD AND APPARATUS FOR PRODUCING BLADES Filed Oct. 9, 1958 llSheets-Sheet 9 I L z u I /;J INVENTOR5.

7 Fen/w M. Far/we iHPE If??? nrmem-y- Se t. 8, 1964 w. A. PAILLE ETAL.3,147,539

7 METHOD AND APPARATUS F OR PRODUCING BLADES Filed Oct. e, 1958 11Sheets-Sheet 10 TLEIZ'] ut? ,3 I24 "/20 v 422p A225 J3 I l i I /Zd) IIIII/II I I III/I I 1111/ I I IIIIIIIIIII United States Patent 3,147,539METHOD AND APPARATUS FOR PRODUCING BLADES Wilbrod Alfred Paille,Luellow, Vt., and Gene Belli, Arlington, and Frank Maxwell Fowler,Beverly, Mass, assignors to General Electric Company, a corporation ofNew York Filed Oct. 9, 1958, Ser. No. 766,346 28 Claims. (Cl. 29156.8)

This invention relates to methods and apparatus for the manufacture ofblades of the type used in elastic fluid flow apparatus and the like.

With the advances made in the design criteria of elastic fluid flowapparatus, such as turbine engines, the required precision in thedimensioning of the blades has made necessary machining, grinding,polishing, and tumble-finishing operations which are costly andtime-consuming. Moreover, manufacturing operations heretofore used donot assure the elimination of subsurface imperfections including folds,laps, and cold-shuts.

It has heretofore been proposed to roll-form the blades from work piecesincluding enlarged heads and by means of which the airfoil section isreduced to approximately its final dimensions.

It is an object of the present invention to provide a method andapparatus by means of which the aerodynamic surfaces of the blades ofsimple and complex shapes may be made in the absence of imperfections ofany character resulting from any part of the blade-forming operationsand by means of which the blades are completely and accurately finishedwith minimum require. ments in respect to final finishing operations.

In carrying out our invention in one form thereof, a blade blank havinga transition region joining a base portion and an airfoil section has across-sectional area which gradually increases from the cross-sectionalarea of the airfoil section to that of the base portion. Such a bladeblank is first reshaped into a blade preform by applying to the backsurface of the base portion a force of large magnitude which, throughpivoted reaction members, develops reaction forces of progressivelyincreasing magnitude angularly directed toward the transition re-. gionsto reshape those regions into the top surface of the base portion and toform smoothly curved fillets from said transition regions. In formingthe fillets, that part of the airfoil section adjacent them has itscross-sectional area reduced so that there may be received therewithinrelatively movable arcuate surfaces of dies which further reshape thefillets and which are also mounted for roll-forming the airfoil section.During the reshaping of the fillets, a substantial force is applied tothe back surface of the base portion to press the base toward the diesurfaces adjacent the curved corner portions thereof.

During the roll-forming of the airfoil section, the force theretoforeurging the base portion toward the roll-forming dies is reversed tomaintain the blade in tension during the roll-forming of the airfoilsection thereof.

Following the roll-forming, the blade preform is placed between a pairof coining dies having metal-shaping surfaces for engaging the airfoilsection, and additional surfaces for engaging the top surface of thebase portion. Concurrently with the coining operations, a force ofsubstantial magnitude is again applied to the bottom face of the baseportion to urge the top surface thereof against opposite surfaces of thecoining dies.

The methods and apparatus characterizing the present invention providegreat flexibility in the manufacturing operations, thus to make possiblethe accommodation of limitations in the starting materials to be usedfor the blades. For example, some metals, such as alloys of the nickelbase type, must be annealed after each extruding,

3,147,539 Patented Sept. 8, 1964 'ice rolling, or upsetting operationbefore further reshaping may be satisfactorily accomplished. In otherinstances, whether the annealing be necessary or unnecessary, there willbe enhancement of product quality by repeating selected method stepsgradually to shape the metal into final form. In accordance with thepresent invention, there are provided provisions by means of which thereis attained precise positioning of the parts for each successive pass,that is, for each repetition of selected steps to be carried out and aswill be more fully described hereinafter.

We have found that in the practice of our methods and by the use of ourapparatus, the aerodynamic surfaces including the' airfoil section andthe top surface of the base portion, except for a slight shaping orrounding of the narrow edge portions, may be brought to their finalfinished form without the need for further treatment of said surfaces.In addition to the production of blades of higher and uniform quality,the present invention has resulted in large and substantial savings inthe manufacture of blades for use in elastic fluid flow apparatus.

In referring to the manufacture of blades, we use that term in thegeneric sense to include buckets, vanes, struts, and equivalentstructures which are known in different arts under different names.

The subject matter which We regard as our invention is particularlypointed out and distinctly claimed in the concluding portion of thisspecification. tion, however, both as to organization and method ofoperation, together with further objects and advantages thereof, maybest be understood by reference to our description taken in connectionwith the accompanying drawings in which:

FIG. 1 is a perspective view of a starting slug;

FIG. 2 is a partial sectional view of the extruded blade blank afterextrusion in and prior to removal from an extruding die;

FIG. 3 is a perspective view of the extruded blade blank;

FIG. 4 is a fragmentary sectional View of the extruded blade blank inour prepinching apparatus prior to the prepinching operations whichproduce a blade preform;

FIG. 5 is an enlarged fractional sectional view of the parts of FIG. 4after the formation of the fillets and prior to upsetting of the base;

FIG. 6 is a fragmentary sectional view of the parts of FIG. 4 in theirfinal positions which produce the blade preform;

FIG. 7 is a diagrammatic illustration of one embodiment of ourprepinching apparatus for forming blade preforms;

FIG. 8 is a force diagram explanatory of the operations performed by theapparatus of FIG. 7;

FIG. 9 is a perspective view of the prepinched blade blank which is alsoreferred to as the blade preform;

FIGS. 10-13 are fragmentary sectional views of the method ofintroduction of the blade preform into the roll-forming apparatus;

FIG. 14 is a fragmentary sectional view of the parts of FIG. 10 and ofthe blade preform after further shaping operations;

FIG. 15 is a fragmentary sectional View of the blade in our roll-formingapparatus in a momentary dwell position just prior to rolling;

FIG. 16 is a fragmentary sectional view of the blade in our roll-formingapparatus just after the initiation of rolling;

FIG. 17 is a fragmentary sectional view of the completion of ourroll-forming operations;

FIG. 18 is a perspective view of the blade after rollforming;

Our inven-v FIG. 19 is a diagrammatic side view of one embodiment of ourmetal-shaping and roll-forming apparatus in the fully opened position;

FIG. 20 is a sectional view taken along the line 2fi-20 of FIG. 19;

FIG. 21 schematically illustrates, with some exaggeration, the manner inwhich the movable die of FIGS. 10 13 moves into and out of registry witha blade preform;

FIGS. 22 and 24 are like FIG. 19 but with the parts in differentpositions;

FIG. 23 is an enlarged fragmentary sectional view of the roll-formingdies in the virtually closed position;

FIGS. 25-28 are fragmentary sectional views of the coining apparatus forthe rolled blade preform illustrating different positions during coiningFIG. 29 is a perspective view of a coined-upset blade; and

FIG. 30 is a perspective view of a trimmed blade.

The present invention is particularly concerned with the operations tobe carried out upon a roughly shaped blade blank 10, such as illustratedin FIG. 3. Though the blade blank 10 may be produced in different ways,we prefer to produce the blank by extruding it from a starting slugillustrated in FIG. 1. A ram 11, FIG. 2, squeezes, or more particularlyextrudes, the material through a shaping die 12, it being understoodthat the starting slug will have been heated to the requisitetemperature to facilitate the extruding operation. After the extrudingoperation, the blade blank will be cleaned preparatory to the nextsequence of operations. The blade blank 10, the blade preform 13, ofFIG. 9, the rolled blade 53 f FIG. 18, and the coined and trimmed bladesof FIGS. 29 and 30 are respectively characterized by the presence of abase 101: having a bottom surface 10e and a top surface 10s and alsohaving an extension 10a forming the airfoil section. A transition region1013, to be shaped into fillets 101, FIG. 5, has a cross-sectional areawhich gradually increases from that of the adjoining portion of theairfoil section until it merges with the top surface 10s of the base10b.

In order to reduce to a minimum the possibility of surface imperfectionsdue to the metal-shaping operations needed to convert the blade blank 10into the substantially finished blade of FIG. 29, the blade blank willfirst be converted into the blade preform 13 illustrated in FIG. 9 andin more detail in the cross-sectional view of FIG. 6. To produce theblade preform 13, the blade blank 10 is, FIG. 4, disposed betweenopposed protuberances 14a and 15a of a pair of dies 14 and 15, theprotuberances engaging the top surface 10s adjacent transition regionltlt. The dies 14 and15 carrying the protuberances 14a and 15a are inturn supported on reaction members, later to be described in moredetail, and so arranged that upon application by a ram 16 of a force 17of substantial magnitude to the bottom surface like of the blade blank10, there will be developed, through movement of die members alongarcuate paths 1-8 and 19, angularly directed forces and 21, FIG. 5,applied to the top surface 10:. at the transition regions 101 to reshapethat surface and those regions to include smoothly curved fillets 10fwhich lie between top surface 10s and a region of substantially reducedcross-sectional area of the airfoil extension 10a.

In reshaping the transition regions ltlt, the protuberances 14a and 15aact upon the top surface 10s and transition regions 102 in a mannerwhich may be visualized, FIG. 4, asmovement of the protuberances 14a and15a angularly toward and into the transition regions 10t. With thisvisualization of the action and with the base 1% for the moment assumedto be in fixed position, it will be seen that as the protuberances 14aand 15a reshape the top surface 19s, metal is displaced by theprotubcrances. Some of the displaced metal moves along the top surface10s toward the airfoil section 19a. Some of it moves outwardly. At thesame time, the airfoil section 19a is lengthened by the reduction in itscrosssectional area in the region ltlr adjacent the fillets 10f. Thus,in the final positions of the protuberances 14a and 15a, FIG. 5, it willbe seen that the smoothly curved fillets 10f interconnect the baseportion 10b and that portion 10r of the airfoil section 10a of reducedcross-sectional area. By reason of the smooth, divided flow of a minimumof metal, there are avoided folds, laps, and surface-closed subsurfacecavities known to those skilled in the art as cold-shuts. In FIG. 5, thedies 14 and 15 are in their final positions, but the metal-shapingoperations have not been completed. It will be noted that there remainslight clearances or unfilled regions or spaces 23 located at therespective edges of the top surface of the blade blank. These spaces 23are filled by upsetting the base 1% in the following manner. As the dies14 and 15 are brought to standstill in the positions shown in FIG. 5,the forces 20 and 21 change from kinetic to potential forces, that is,they become holding forces. The force 17 is then effective, FIG. 6, tocause flow of metal into the spaces 23. This metal flow results from anupsetting action which, though not needed, may sometimes also produce aslight outward flow of metal at the back surface 10@ into the area 16a,and as best illustrated by the flash 10m in FIGS. 6 and 9.

To set forth the important features of the invention thus far describedhas required step-by-step treatment. In practice, and as will now beexplained, the foregoing operations are smoothly, continuously andrapidly carried out upon actuation of a press which moves the plunger orram 16 from an initial position to a final position after which itreturns to its initial position.

In a preferred form of the invention, FIG. 7, the dies 14 and 15 withtheir curved protuberances 14a and 15a are carried by two reactionlevers or members 25 and 26 respectively pivoted at their remote ends bypivot pins 27 and 28 to a supporting structure or frame 30, preferablyof steel. The levers or reaction members 25 and 26 produce inconjunction with the blade blank 10 a toggle action which uponapplication of a substantial force to the back surface 10e developsreaction forces R, FIG. 8, applied toward the transition regions 101 ofthe blade blank 10. These forces R rapidly increase upon displacement ofthe reaction levers 25 and 26 from their initial positions toward theirfinal positions.

In their initial positions the levers 25 and 26 lie at angles a measuredfrom a line 31 interconnecting the axes of their pivotal mounting means27 and 28. This angle or is preferably relatively small with thereaction levers 25 and 26 in their initial positions and decreases toabout ten degrees or less with rotation of the levers about their pivotpoints in directions to reduce the separation distance between theprotuberances 14a and 15a, thereby to produce the smoothly curvedfillets 101, FIG. 5, and to reduce the adjacent cross-sectional area 10rof the airfoil section. More particularly, if the entire actuating forceP, FIG. 8, be applied to the back surface 10e by the mechanically orhydraulically actuated thrust member 16, there will arise oppositelyacting reaction forces 1. Mathematically, P=2p. However, the reactionforces R will be of greater magnitude than the applied force P and manytimes the magnitude of each opposing force p. Mathematically,

2 sin a This expression means that as the angle a approaches zero, thesine of a approaches zero. Accordingly, the reaction forces R rapidlyincrease, with value infinity as their limit. Stated differently, thereaction forces R increase inversely as the cosine of the angle Abetween the side p of the force diagram of FIG. 8 and the hypothenuse Rthereof. The maximum magnitude of forces R tend to be limited byelongation of the base plate 30, of steel. The elongation of the heavysupporting plate is small but play its part in controlling themagnitudes of the forces applied to blade blank 10.

With the foregoing understanding of the force diagram and the manner inwhich the reaction forces R are directed angularly toward the transitionsections, it will be understood that the metal-shaping forces maycomprise forces applied directly to the levers 25 and 26 concurrentlywith the application to the back surface a of a force to hold the bladeblank into the position illustrated in FIG. 7 and to maintain it betweenthe protuberances 14a and a until the final positions of the die membershave been attained, as illustrated in FIGS. 5 and 6.

As shown in FIGS. 4-7, the force-applying means 16 is provided with arecess 16a within which the base portion of the blank 10 may nest, withclearance with the walls of the recess. The depth of the recess isselected to control, in conjunction with the recess 32 in FIGS. 4 and 7jointly provided by the die structures, the thickness of the base of theblade preform when the force-applying means 16 is brought to its finalposition as shown in FIG. 6. The peripheral end surface 16b, FIG. 5,then engages the top surfaces 14b and 15b of the die members which formstops for ram 16. Thus, there is predetermined in accordance with thecombined depth of the two recesses 16a and 32 the desired thicknessneeded to control the base of the blade preform of FIG. 9. The recess 32provided by the dies 14 and 15 has walls which also predetermine thedimensions of nearly all of the side wall portions of the base 10b,since in the upsetting operation carried out in the apparatus the metalof the base portion is upset until there is intimate contact with thewalls of that recess. However, the recess 16a provided in theforce-applying member 16 is of greater cross-sectional area than recess32 to provide clearance circumferentially about the bottom face 10a,thereby to provide the earlier mentioned metal-flowing space toaccommodate flash 10m. Such a metal flow occurs during the upsettingoperation in varying degree dependent upon the mass of metal initiallycomprising each base portion and resulting from the above-describedextruding process. Though the mass of each base portion will berelatively uniform, there will be some variation which will result inflashes or metal flows 10m, FIG. 9, of differing degree. As shown inFIG. 6, there will in most cases be some free space about the finalflash that may be formed. In the final position of the dies, as shown inFIG. 6, the base of the blade blank will have been reshaped so that itsrespective surfaces will intimately contact and conform with allsurfaces of the walls forming the recess 32.

It will be further observed, FIG. 7, that as the reaction levers and 26are moved downwardly with decrease in the angle a, the lower portionsthereof come to rest against fixed stops 33 and 34. As soon as thesestops are engaged by the reaction levers, the reaction forces R becomeholding forces. The continued application of the force P as by themember 16 produces the final upsetting operation which has just beendescribed. At this point the force P may be reduced to zero,hydraulically by operation of control valves, or mechanically by thepassage of the stroke-applying means past the dead-center position.Thereupon, springs 35 and 36 are effective to rotate the levers 25 and26 to return them to their initial positions. At the same time, there iseffective a piston or spring means 37 to actuate upwardly an ejector 38,extending through an opening in the base plate 30, into engagement withthe air-foil section 10a to move the blade blank outwardly of thelevers. The upward move ments of members 25 and 26 are limited byadjustable stops 39 and 40 carried by members 25 and 26.

The angular movement of dies 14 and 15 with the protuberances 14a and15a in predetermined initial positions, as shown in FIGS. 4 and 7,assures accurate positioning of each blade blank. This feature is ofimportance when the characteristics of a particularly alloy require asuccession of the processing operations to bring the initial blade blank10 to the desired dimensions for the blade preform 13 of FIG. 9.

Since the positioning of each part relative to the die members iscertain and automatic, the metal-shaping operations always take placealong the top surface 10s and and including the transition regions 10tadjacent the airfoil section 10a.

1 With the blade preform 13 brought to its desired dimensions, which ingeneral will include the diminution at 102' of the cross-sectional areaof the airfoil section adjacent the fillets 10 to slightly larger thanthe final cross-sectional area of the finished airfoil section, thesecond stage in fabrication of the finished blade can begin after therehas been removed from the preform any flash, such as shown at 10m.

In some cases it will be desirable to clean and anneal the blade preform13 before initiating the roll-forming operations now to be described.The cleaning operations will be essential for those cases in which thepreforming or prepinching operations are carried out on blade blanks thesurfaces of which have been contaminated such as by oxidation.

As illustrated in FIG. 10, the blade preform 13 of FIG. 9 is securelyheld by holding means 42 which though biased upwardly, moves in thedirection of arrow 43 to place the blade preform between the pair of diemembers 44 and 45 relatively movable one with respect to the other todecrease the separation distance between curved metal-shaping cornersrespectively interconnecting shoulder portions 44a and 45a and curvedsections 440 and 45c. As shown, the die member 44 is moved downwardly.Its engagement with the airfoil section 1011 tilts the airfoil sectiondownwardly at the same time the holding means 42 is moving the preform13 inwardly toward the shoulders 44a and 45a. In the final position ofthe parts as illustrated in FIG. 14, the top surface 10s of the preform13 is pressed against the shoulder portions 44a and 45a by a forceindicated by the arrow 46 and the blade preform is no longer biasedupwardly.

The holding means 42, as later illustrated, is mounted for rotarymovement upon engagement of the upper surface of the airfoil section10a, as shown in FIG. 10, by the die 44, the holding means 42 as a wholebeing biased to maintain the airfoil section 10a against the die 44, butwithout substantial opposition to said rotary move! ment. Thepositioning of the blade preform between the dies is certain and adaptedto the positioning of blade preforms for a succession of operations ofthe type to be described in avoidance of any possibility ofconsequential galling and undesired disturbance of the airfoil surfaces,particularly the top surface 10s.

Referring now to FIGS. 11-13, the die 44 is moved toward the bladepreform 13 and toward die 45 along an arcuate path, later to bedescribed in more detail in connection with FIG. 21. Such a path isindicated generallyby the successive positions of die 44 and arrows 41which show the change in direction of movement.

As shown in FIG. 11, as die 44 pivots blade preform 13 toward die 45,the spaces or gaps 47, 47a, 48 and 48a are decreased, gap 47 beinggreater than gap 48 because of the upward bias of the blade preform.These spaces or gaps are shown somewhat exaggerated for clarity orillustration. The blade preform, therefore, is moved downward as well astoward the dies generally in the direction of arrow 43. i

' Die 44 continues to move blade preform 13 toward die 45 until contactof the preform with die 45 is made, FIG. 12. Blade preform 13 is stillbiased upwardly allowing the nose portion of die 44 between surfaces 44aand 44c to fit accurately and snugly into the fillet of the preform. Asthe above described nose of die 44 closes into the fillet, force isapplied the resultant of which is shown by arrows 49 and 49a to shapeand form the fillet area. The blade preform 13 now is no longer biasedupwardly. As shown in FIG. 13, gaps 47, 48, 47a and 48a still exist butnow are nearly symmetrical about center line 110.

Preferably, the forward movement of the holding means 42 is arrested asthe parts approach the position shown in FIG. 12. As the die 44 arrivesin about the position of FIG. 13, the arresting means is freed by themovement of die 44. The holding means 42 is then moved positively andsynchronously with die 44 until the parts attain their final positionsas shown in FIG. 14. The top surface 19s is then seated against theshoulders 44a and 45a. There is concurrently applied a substantial force46, FIG. 14. There will be achieved any needed further reshaping of thetop surface 10s and of the fillets to conform with the surfaces of thedies 44 and 45.

The holding means, as best shown in FIGS. 11-13, has opposite horizontalsurfaces 42a and 4212 which cooperate with guiding surfaces 445 and 45bto establish a fixed and reproducible vertical relationship between thebase portion 10b and the airfoil section 10a. With this relationshipestablished, FIG. 13, the force 49 moving the die member 44 into itsfinal position will develop a reaction force 49a. These forces are bothangularly directed toward the fillets. If the fillets be of shape otherthan in exact conformity with the curved nose portions of each die, theywill be reshaped into exact conformity therewith.

As will be shown later, FIG. 20, this vertical relationship iscomplemented by a controlled horizontal relationship to assure exact andreproducible location of the blade preform 13 relative to the dies 44and 45 if consecutive roll forming operations are to be performed.

With the final positioning of the blade preform between dies 44 and 45,and upon completion of the fillet and top surface sizing operation, thedies are maintained in fixed space relationship one to the other for ashort dwell time, FIG. 15. At that time kinetic forces 46, 49 and 49a ofFIG. 14 become potential forces 46a, 49b and 490, FIG. 15, to hold thepreform and allow the metal sized to complete its flow or movement. Thedwell time may be accomplished by a series of controls, later to bedescribed in connection with FIGS. 19, 22 and 24.

The dies 44 and 45 are then relatively rotated, arrows 50, FIG. 16, toroll-form the airfoil section 10a. The roll-forming is accomplished withthe blade preform 13 maintained under tension, as shown by arrow 51, atension of magnitude adequate to prevent the preform from following thecurved portions 44c and 450 of either of the dies and of a magnitudewhich is maintained substantially constant, notwithstanding changes inthe surface speeds of the curved die surfaces 440 and 450. The rollingforces are generally indicated by arrows 52. In FIG. 16 the bladepreform has been shown in a position slightly displaced to the right bythe curved surfaces 44c and 45c from the position illustrated in FIGS.14 and 15. The rolling action continues, as shown in FIG. 17, to reducethe cross-sectional area of the airfoilv section and to shape it intoconformity with the die surfaces 440 and 450. As the tip of the airfoilsection leaves the curved die surfaces, a bias on the holding means 42tilts the rolled blade preform 53 upwardly and away from the diestructure and to the broken-line position for easy removal upon releaseby the holding means 42. The rolled blade preform 53, FIG. 18, hassmooth airfoil surfaces 10a and has a controlled thickness throughoutthe intended length thereof. Thus the blade preform 53 has a length andwidth materially greater than that required in its final form. Theirregularities illustrated at the tip end can occur as the result ofrepeated rolling operations and by relief (increased spacing between thecurved surfaces 440 and 450) after the useful portion of the airfoilsection has been accurately brought to the desired roll-formeddimensions.

Referring now to FIGS. 19-23, there has been illustrated a preferredapparatus for reshaping the top surface of the blade preform 13 and toroll-form the airfoil section in manner already described. Thus, FIG.19, the die 45 is carried by a roll 55 carried by a shaft 56 pivotedbetween upturned portions 57a of frame 57. Thus the roll and the die 45are held in fixed position relative toframe or foundation 57. The die 45may be rotated upon movement toward the left of a link 63 pivotallyconnected through a pivot pin 62 to the ends of a pair of levers 61which have their opposite ends secured to roll 55. The link 63 has itsopposite end connected by pivot pin 64 to an equalizing link 65.Equalizing link 65 is secured to the piston or ram 67 of a hydraulicoperator 68 by a pivot pin 66 located at a point midway on equalizinglink 65 and slightly to the left of a line through the center of pivotpins 64 and 77.

The bodily movable and rotatable die 44 is carried by a roll 78supported by a shaft 71 guided by arms 72a and 72b of a supportingstructure pivoted by shaft 73 to frame 57. Levers 74 secured atcorresponding ends to roll extend upwardly from roll 70 and by pin 75are pivoted to one end of a link 76, the opposite end thereof beingconnected to equalizing link 65 by pivot pin 7 7 Pivotally connected topin or stub shaft 71 is a ram member 78, mechanically or hydraulicallydriven for bodily moving die 44 toward and away from die 45. It will berecalled that the dies 44 and 45, FIG. 10, have faces 44a and 45a whichterminate in the curved edge or nose portions which merge with arcuaterolling surfaces 44c and 450. Since the dies 44 and 45 rotaterespectively about the axes of shafts 56 and 71, it is important duringthe movement, bodily, of the die 44 toward die 45 that the piston 69 ofoperator 68 for rotating the dies shall exert sufficient force tomaintain continuous contact between link rods 63 and 76 and theirrespective stops 83 and 84. This may be accomplished by any suitablemeans, such for example, as a hydraulic actuating system which normallyfrom a sump tank 80 and a constant volume pump 81 applies through apressure line 82, a one way valve 82a and a solenoid valve 87a ahydraulic pressure to the left hand side of piston 69. In thisarrangement, piston 69 maintains a forward velocity depending on therise or fall of ram 78 and hence arms 72a and 72b. This maintains links63 and 76 in the positions illustrated in FIG. 19. The lower end of link63 abuts against an adjustable stop 83 carried by frame 57. Theright-hand end of link 76 abuts against an adjustable stop 84 carried bya crossmember interconnecting arms 72a and 7212. Thus, the die 45 willnot rotate as die 44 is moved. toward it, and equalizing link 65 rotatesto equalize links 63 and 76.

There is included in the pressure line 82 a pressure relief valve 85having an adjusting means to predetermine the magnitude of the hydraulicpressure which may be applied to an operator 86 as well as to maintain aminimum pressure in line 82 and hence in operator 68. That is, thepressure relief valve 85 assures a differential pressure as betweenoperators or actuators 68 and 86 so that the pressure on actuator 68 isalways materially in excess of that applied to the actuator 86.

Assuming now that the solenoid valve 78a is in the position illustratedin FIG. 19, the fluid from pump 81 first forces piston 69 to the rightto cause contact of links 63 and 76 with their respective stops 83' and84 as shown. Then, when pressure in line 82 exceeds the adjusted minimumof relief valve 85, line 82 becomes pressurized. When solenoid valve 87bis actuated into the posithun shown in FIG. 9, fluid will act on piston88 to move it to the left. In so moving, it displaces air into apressure or air tank 89. This compressed air is utilized to place thepreform 13 under tension during roll forming and also to return shuttle90 to the position illustrated in FIG. 19.

It will be further assumed that a preform 13 has been inserted in theholding means. The blade preform may be readily placed in the holdingmeans 42 since the shuttle 90 carrying it is held in an upwardlyinclined position by a roller 91 engaging an extension 92 of the shuttle90. It is convenient, though not essential to the invention, to elevatethe holding means as illustrated in FIG. 19 for ease in placing theblade preform within the holding means which is then operated to holdsecurely the preform by an actuating means 93. The details of theholding 9 and actuating mechanisms are conventional and, therefore, havenot been illustrated in detail.

With the blade 13 held, and hydraulic fluid admitted to the actuator 86,the shuttle starting switch is activated and the piston rod 94 moves theshuttle 90 along guideways 95 of a carriage 96 to move the blade preform13 toward the dies 44 and 45. Shuttle 90 will be moved to the left untila stop 90a and a switching means 90b on shuttle 90 contacts a stop 99con carriage 95 to actuate ram 78. The carriage 96 is also slidable,supported in guideways 97 of the main frame 57.

As the shuttle 90 moves away from roller 91, it rotates by gravity ormay be positively moved by a spring, not shown, about the pivot pin 98which is roller-mounted in guideways 95 of carriage 96. As the shuttledescends, its lower surface engages an upwardly biased plunger 99. It isthis plunger that positions the preform 13 in the angular position shownin FIG. for entry between the dies 44 and 45.

As the blade preform 13 is moved beneath the upper die 44, switchingmeans 90b initiates a downward movement of that die member through themechanically or hydraulically actuated ram means 7 8 which are pivotallyconnected to shaft 71. This downward movement, incident to the use of amechanical press actuator, will be quite rapid. Accordingly, to assureaccurate and precise registration of the preform 13 between the diesprior to engagement with any part of the preform, there is providedsynchronizing means comprising actuating levers 101 pivoted at 102,which normally through the action of a spring 103 maintain carriage 96in its right-hand position. The levers 101 can move the carriage 96 tothe left or toward the dies by a predetermined amount. Thus whenadjustable actuating surfaces 104 carried by the arms 72a and 72b engagethe upper surfaces of the levers 101, there is a rapid movement of thecarriage 96 to the left, against the bias of spring 103 to produce theforce represented by arrow 46 of FIG. 14 and to seat the top surface 10sof the blade preform 13, FIG. 14, against the surfaces 44a and 45a atthe same time that the curved nose portions of the die members 44 and 45are moved inwardly into and against the fillets of the blade preform 13as has been previously described. Inasmuch as the move ment of carriage96 is produced entirely by the engagement of levers 101 by the surfaces104, there is synchronized and precise movement of the preform 13 intoand between the dies 44 and 45 as shown. In this connection, it is to benoted that the top surface 10s throughout a major portion of its areaengages surfaces 44a and 45a for precise positioning. That top surface10s is maintained against surfaces 44a and 45a with a force equal tothat developed by the actuator 86. Actuator 86 will counteract anyover-travel of the carriage 96 beyond the point where the top surface19s and the surfaces 44a and 45a are in engagement, as shown in FIGS. 14and 15. Such over-travel of the carriage 96 cannot be transmitted to theshuttle 90, since there is a corresponding right-hand movement of thepiston rod 94 of the actuator 86 relative to carriage 96, thus to permitthe shuttle 90 carried thereby to remain stationary relative to surfaces44a and 45a. The levers 101 are provided with adjustable stops 105mounted in frame 57 to adjust the travel of carriage 95 produced bybiasing means 103.

Since the upper die 44, FIGS. 10-13, has surface 44a disposed in sharpangular position relative to the curved surface 440, it is importantthat there be minimized any possibility of engagement of the curved edgeor nose portion of the die 44 with the upper corner of the blade preform13 as the dies are moved inwardly. Accordingly, the die 44 is arrangedto swing about an are 107, FIG. 21, which generally can be described asbeing tilted away from the final position of surface 19s. Moreprecisely, and as best Shown in FIG. 21, a tangent 1118 from the arc ofmovement of die 44, taken from the point 109 of intersection thereofwith the center line 110 formed by a trace of the centralairfoil-rolling plane between the die members 44 and 45, lies at anangle A to a line perpendicular to the line 110. This angle A isproduced by locating the axis of shaft or pivot pin 73 for thesupporting arms 72a and 72b at a point nearer the die 45 than the die 44and particularly in a direction displaced toward die 45 from the line119 as indicated by the somewhat exaggerated displacement dimension X inFIG. 21.

FIG. 21 alone does not delineate in full the positioning of die 44 as ittraverses its arcuate travel path 107. Thus in FIG. 21, the arc is shownas passing through the curved nose portion of die 44.

As best shown in FIGS. 19 and 20, it will be noted that the dies 44 and45 are carried by the rolls 70 and 55 midway thereof and with thearcuate surfaces, FIG. 23, 10-,

cated so as to leave a very slight spacing as indicated at 114, 115 oneither side of the die cavity 112. With the dies in the positions ofFIGS. 22 and 24, the rim portions 55a and 70a of the rolls 55 and 70engage each Othwd thus absorb the downward force applied by theactuating means 78. The rollingpressure on the airfoil section of thedie is thus applied indirectly rather than directly from the actuatingmeans 78. Thus, the rim portions of the rolls 55 and 70 may be loaded toa greater extent than is actually required by the dies 44 and 45. Theeffect of the increased loading is to insure that the dies will performtheir rolling functions, since the rolling forces will be maintainednotwithstanding any slight deflection that may occur in the apparatus.This is a factor contributing to the high quality of the product. Asshown in FIG. 20, shock absorbers 116 in the form of rubber cushions maybe included on the frame 57 to absorb kinetic energy from ram 78 andconnecting parts. Thus damage to the rims 55a and 70a is avoided.

As was mentioned before in connection with FIGS. 11-15, surfaces 42a and42b on the holding means 42 cooperate with guiding surfaces 44b and 4512respectively to establish a fixed and reproducible vertical relationshipbetween the base portion 10b and the airfoil 10a. A similar fixed andreproducible horizontal relationship is established through thecooperation of surfaces 7% and 55b, FIG. 20, with vertical side surfaces420 of holding means 42, FIG. 19. Thus guiding surfaces on the rims androlls cooperate with guiding surfaces on the holding means to estabish afiXed and reproducible positioning of the blade preform 13 in both thehorizontal and vertical directions. This precise positioning arrangementallows accurate consecutive operation of rolling cycles thereby avoidingscuffing on recycling of the surfaces already formed.

With the dies closed, FIG. 22, and after the reshaping of the fillets bythe movement of the force-producing means 78 from its initial to itsfinal position to bring the dies to their final positions, as shown inFIGS. 14 and 15, a solenoid operated valve 87a is actuated by timedswitching means 113 being contacted by arm 72a to transfer the hydraulicpressure to the right-hand side of piston 69 for actuation of the pistonrod 67 to the left. Through the equalizer link 65, the links 63 and 76rotate the dies 44 and 45 in directions indicated by arrows 50, FIGS. 16and 17, to roll-form the airfoil and in a manner above described inconsiderable detail.

As the valve 87a is actuated to apply the roll-forming .l'orces to thedies, the valve 87b is rotated to connect the oil-filled portion of theactuator 86 to the sump. Accordingly, as soon as valve 87b connects theoil-filled portion of the cylinder to the sump, the compressed air oftank 89 is effective on the piston 88 of actuator 86 to apply a force tomove it to the right. This force indicated at 51, FIGS. 16 and 17,places the blade preform 13 under tension during the rolling operations.The parts in positions during the roll-forming are shown in FIG. 24.Upon termination of the rolling operations, the compressed air iseffective in returning the shuttle 90 to the illustrated position inFIG. 19 at which point 1 1 it contacts switching means 113a to raise ram78. The spring 103, FIG. 19 returns carriage 96 to its right-handposition, the heads of cap screws 105 threaded into the frame 57 servingas stops for levers 161 and for the carriage 96.

It is important to note that the intermediate pivotal connection 66between the equalizer link 65 and piston rod 67 is displaced to the leftfrom a line interconnecting the axes of pivotal connections 64 and 77 oflinks 63 and 76. By rotation of link 65, FIG. 24, about pivot pin 66 theresult of this equalizerof the negative typeis to maintain an optimumbalance between the surface speeds of the dies 44 and 45 with a tendencyto keep the movement of the dies in proper synchronization. Such actionminimizes any slippage or sculfing between the curved die surfaces andthe airfoil. Surfaces of improved character are thereby attained on theopposite faces of the rollformed airfoil a of FIG. 18. The absence ofslippage as between the dies and the airfoil surfaces also represents ahighly favorable factor in extending the life of the dies. The equalizerlink 65 is important to each roll-forming operation by reason of thefact that one surface of the airfoil section is convex and the otherconcave, as best shown by die cavity 112, FIG. 23, thus requiringdifferent rolling curvatures of the dies and, in general, differentresistance to roll-forming. It will be noted that the line of action ofthe piston rod 67 is displaced upwardly from the axis of rotation of thearms 72a and 72b about shaft 73. Accordingly, after completion of therolling action, a reversal of movement of the piston rod 67 will,through the linkage means, produce a reverse rotation of the two dies toreturn them to their starting positions, notwithstanding any degree ofdisplacement that may have occurred during the roll-forming operations.This assures accuracy in the return of dies 44 and 45 into the fillet 10if subsequent roll forming operations are required.

Upon completion of the roll-forming of the airfoil section, the valves87a and 8715 are returned to the positions shown in FIG. 19.

As the actuator 68 moves rod 67 to the right, the link 65 will bepivoting about its axis 66, while the links 63 and 76 will be rotatingthe dies 44 and-45. Concurrently, the die 44 will be moving upwardly byreason of the upward movement of the force-applying member 78. Thoughthe spring-biased plunger 99 will already have lifted shuttle 90 toabout the position shown by dotted lines in FIG. 17, as the extension 92engages roller stop 91, the shuttle will be further tilted. to theposition of FIG. 19 for easy removal of the finished roll-formed bladeupon release of the holding means by the actuator 93.

After the required number of roll-forming operations on each bladepreform, the roll-formed blade will be ready for the coining operationswhich will now be described.

The first step, FIG. 25, in the final coining operation is to placerolled blade preform 53 between a pair of dies 120 and 121 which, asshown in FIG. 25, are initially in spaced relation one to the other. Thepositioning of the preform 53 between the coining dies is accomplishedby holding the base portion 10b in a recess of what may be termed anvilmembers 122a and 12% adapted to be actuated to press the top surface 10sof the preform 53 against the shoulders 120a and 121a of coining dies120 and 121 after they have been substantially closed, FIG. 27, andtheir curved corner portions have seated, or substantially seated,against the curved fillets 10 The anvil or supporting members 122a and122b are moved to positions where the top surface 10s of blade 53 willengage the surfaces 120a and 121a, a force 123, FIG. 27, being developedof magnitude adequate to assure a sizing, smoothing ironing, or finalfinishing operation on that top surface. In order that the foregoingoperations may be closely controlled, the anvil members 122a and 12211are moved in synchronism with the closing of the coining dies and 121.This synchronous movement, which takes place as the coining dies closeupon the airfoil section, is accomplished, as best shown in FIG. 25, bymoving together both the coining die 120 and an actuating member 124 asby actuating means hydraulically or mechanically operated as by a togglepress so that as the coining die 120 moves toward the coining die 121,the actuating member 124 through its inclined surface 124a engages amating inclined surface 122s of the anvil 122a to move the latter alongways of frame 131 toward the right at a speed preferably greater thanthe closing movement of the coining dies. The greater speed of the anvilor supporting member 122a will be accomplished if the angle as measuredfrom the horizontal line of movement of member 122a to the inclinedsurfaces is less than 45.

The top surface 10s and the fillets are reshaped as the coining diesengage the airfoil section 100 but in avoidance of any displacement ofmetal in any portion of the aerodynamic surfaces of a character whichwill give rise to any laps, folds, or cold-shuts. The coining operation,which is both a sizing and a final shaping operation of the aerodynamicsurfaces, brings into the final desired configuration the airfoilsurfaces. As best shown in FIG. 25, the coining surfaces 12Gb and 121krespectively extend upwardly at an angle to the faces 120a and 121a toestablish a relationship suitable for certain types of blades. Thecoining surfaces may extend at any suitable angle which will bedetermined by the slope of the top surface 10s which is heldperpendicular to the movement of die 120.

For the rolled preform 53, the coining surfaces 12012 and 121b areinclined upwardly at an angle such that a line extending through whatare termed by those skilled in the art as stacking points in the finalcoined blade will be at a predetermined angle with reference to surface10s. In this manner, the coining dies after engagement of the airfoilsurfaces impart thereto the warp and other final configurations desiredin that section. It will be desirable to actuate the coining dies by atoggle press in order to provide a dwell of the dies in their finalpositions, that is, a short interval in which the dies are atstandstill. The dwell provides time for the metal to flow into its finalconfiguration.

With the parts in position preparatory to the coining operation, FIG.25, the anvil member 122a is biased, as by spring assemblies 132, to theleft and against a stop member 133. As the die 120 and actuating member124 are moved downwardly, arrow 138, the shoulder or forming face 120aof die 120 has adequate clearance as indicated at 134, FIG. 25, with thetop surface 10s of the preform 53 to minimize any possibility ofcontacting the preform during closure of the coining dies. It will alsobe observed that the anvil 122i) slidably carried in dovetail ways 122wof anvil 122a is biased upwardly by spring assemblies 135, a shoulderportion engaging a mating shoulder of the anvil member 122a to limitupward movement thereof.

As shown in FIG. 26, the outer tip of the airfoil portion 10a of rollpreform 53 is resting on the upper surface of the coining die 121. Themovable die 120 has its nose portion engaging the airfoil sectionadjacent the top surface ltis. The inclined surface 124a of actuatingmember 124- has almost engaged the mating surface 122s. The engagementof the nose portion of coining die 120 with the airfoil section 10a hasdisplaced downwardly the anvil 122b, as will be evident from acomparison of the positions of the parts in FIGS. 25 and 26. Thus, somebending of the airfoil section 16a has taken place with the parts in thepositions shown in FIG. 26. In this connection, it will be understoodthat the base portion 10b of the preform 53 is securely held in theanvil recess. As the die-closing movement continues, the airfoil section10a is further bent upwardly relative to the base ltlb.

13 As the die 120 moves from the position of FIG. 26 through theposition of FIG. 27 to the position of FIG. 28, the inclined actuatingsurface 124a of actuating member 124 engages the mating surface 122s ofanvil member 122a to produce from force 139 a force 123 and rapidly tomove the anvil members 122a and 12212 to right to seat the top surface sagainst the shoulders or opposing surfaces of the dies 120 and 121 inmanner above described. It is to be noted, FIG. 27, that surface 10s isworked prior to complete coining of airfoil 10a. In the final positionof the coining dies, FIG. 28, the anvil 12% seats against the frame 131to limit the downward movement thereof.

Upon completion of the reshaping of the top surface 10s including thefillets 10 and the coining of the airfoil section 10a, the coining dies120 and 121 are separated and the coined blade, as illustrated in FIG.29, removed therefrom. The blade is then trimmed to predeterminedlengths and width, i.e., which are desired for the particular assemblyof blades in a particular assemblage or stage thereof. The length andWidth trimming lines, FIG. 29, illustrate, with some exaggeration, thewaste metal. The concurrent trimming to width is to meet therequirements of the particular aerodynamic application in providing thethicknesses at the leading and trailing edges needed in the finalairfoil section. After the final trimming operation, FIG. 30, it is onlynecessary to remove trimming burrs and slightly to round the leading andtrailing edges of the airfoil section to bring them into c011- formitywith the aerodynamic requirements for the application to which the bladeis to be applied. The final blade will represent a smoothly curvedsurface from front to back and including the forward and trailing edges.

Though not essential to the invention, it will be noted that the coiningdies 124 and 121 have been respectively provided with a despression 136and a pointed projection 137 to punch a hole 138 or to place a dimplein, or to pierce, the waste airfoil portion of the coined blade. Byproviding such a hole or dimple through that waste portion, therecan beaccurately established the distance from the base portion to the hole ordimple. Accordingly, with this reference point formed into the coinedblade, the trimming line may be established with needed precision forproducing matching blades of identical width and length and in thecorrect orientation relative to the top surface of the base in referenceto the aforesaid stacking points.

With the above understanding of the operations by means of which thepresent invention may be practiced, those skilled in the art willunderstand how to adapt existing machines and/or to build other machinesto carry out the method aspects of the present invention.

After the final trimming operations, the completed blade of FIG. 30 willthen have the base portion 10b machined to size for assembly, such forexample, as to form the driving and driven parts of gas turbines and forair compressor applications. For applications of this kind, blademanufacturing costs have been greatly reduced as a result of the presentinvention, and the blades resulting from the methods and apparatusdescribed above are suitable for turbo-jet engine applications.

This application is a continuation-in-part of our application Serial No.738,528, filed May 28, 1958, for Improved Method and Apparatus forProducing Blades, now abandoned.

1 What is claimed is:

1. The method of manufacturing a blade preform from a blade blank havingan enlarged base portion and a centrally disposed extension ofmaterially smaller crosssectional area and including angular transitionregions between the base portion and said extension, which comprisessuspending from said transition regions said preform by rounded convexsurfaces of opposed dies, applying solely to the back surface of saidbase portion opposite the centrally disposed extension a force to movesaid preform along a metal-forming path extending intermediate saiddies, developing from force opposing forces respectively directedwgularly toward said transition regions of said blade blank thereby tomaintain said preform in position for continued engagement by saidrounded surfaces of said dies during its movement along saidmetal-forming path, increasing said force applied to said back surfaceto metal-moving magnitudes, and concurrently increasing said angularlydirected opposing forces in proportion to the quotient of said forceapplied to said back surface divided by the sine of the angle between aline normal to the direction of that applied force and the angulardirection of each of said opposing forces, said angle decreasing as saidpreform moves through said metal-forming path, said applied force andsaid angularly directed forces of increasing magnitude moving metal individed flow from said transition regions, some outwardly and someinwardly, relative to said extension to form rounded concave filletsfrom said transition regions with concurrent reduction in the cross-sectional area of said extension adjacent to said fillets and withconccurent increase in the length of said extension.

2. In the method of claim 1, in which two roller dies are bodily movedtoward each other to bring two rounded corners thereof into engagementwith said shaped transition region, as said corners engage said filletsapplying a compressional force to said back surface of said bladepreform to press its top surface toward and against shoulder portions ofsaid roller dies, rotating said roller dies to reduce outwardly fromsaid region of reduced cross-sectional area of said airfoil section thethickness of the airfoil section and reversing said compressional forceto maintain said blade preform under tension during rolling, saidreversed force being applied generally tangentially to said roller diesto minimize curvature of the airfoil section of said blade during saidrolling thereof.

3. In the method of claim 1, in which two roller dies are bodily movedtoward each other to bring two rounded corners thereof into engagementwith said smoothly curved fillets, as said corners engage said filletsapplying a compressional force to said back surface of said bladepreform to press its top surface toward and against shoulder portions ofthe dies to reshape said top surface including said fillets, rotatingsaid roller dies toreduce outwardly from said region of reducedcross-sectional area of said airfoil section the thickness of theairfoil section, and reversing said compressional force to maintain saidblade preform under tension during rolling, said reversed force beingapplied generally tangentially to said roller dies to minimize curvatureof the airfoil section of said blade during said rolling thereof.

- 4. The method of claim 2 in which said rolled blade preform isdisposed between two coining dies having opposed surfaces to impart tothe surfaces of the airfoil section their final finished shape andhaving adjacent end surfaces which through curved edge portions arejoined to said opposed surfaces, moving said coining dies toward eachother to impart to said airfoil section its final finished shape, andconcurrently with the movement of said coining dies toward each otherapplying to the back surface of said base a material-shaping force toreshape said top surface .into conformity with the end surfaces of saiddie and to reshape said fillets in conformity with said curved portionsof said die.

5. The method of claim 2 in which said rolled blade preform is disposedbetween two coining dies having metal-shaping surfaces in planesgenerally normal each to the other, and upsetting the base top surfaceand fillet area simultaneously with the coining of the airfoil section.

6. The method of claim 2 in which said rolled blade preform has itsairfoil se'ction disposed between the coining surfaces of coining dies,having their coining surfaces oriented in conformity with theaerodynamic configuration desired in the finished blank and in which thebase top surface is disposed adjacent the end surfaces of the coiningdie, said end surfaces having shapes to establish the desired finalshape of the top surface in relation to said aerodynamic configuration,the additional steps of upsetting the base top surface and fillet areaby applying metal-shaping pressures to the back surface of the basewhile simultaneously coining between the coining surfaces said airfoilsection to bring its aerodynamic surfaces into their final finishedshape.

7. In a method of manufacturing a blade preform from a blade blank whichin a transition region joining a base portion and an airfoil sectionthereof has a cross-sectional area which gradually increases from thecrossrsectional area of the airfoil section to that of the base portion,the steps which comprise applying a force solely to the back surface ofsaid base portion opposite said airfoil section for moving said bladeblank along a metal-shaping path, applying to two opposite faces of saidtransition region reaction forces developed by said blank-moving force,and concurrently increasing the magnitude of said blank-moving force andsaid reaction forces with movement of said blank, said reaction forcesbeing applied to said transition region by rounded fillet-formingsurfaces of two dies which upon increase of said forces shape saidtransition region into smoothly rounded fillets, said rounded surfacesprotruding toward each other to reduce the cross-sectional area of saidairfoil section in the region immediately adjacent said fillets.

8. In a method of manufacturing a blade preform from a blade blank whichin a transition region joining a base portion and an airfoil sectionthereof has a cross-sectional area which gradually increases from thecross-sectional area of said airfoil section to that of said baseportion, the steps which comprise moving convex fillet-formingprotuberances of two dies into engagement with opposite faces of saidtransition region intermediate the ends thereof, applying to the backsurface of the base of said blade blank opposite said airfoil sectionthe sole materialshaping force to move said blank bodily toward saidprotuberances while progressively decreasing the spacing between saidprotuberances, thereby to develop from said material-shaping forceconcave fillet-forming reaction forces, and shaping said transitionregion into smoothly minating in a region of reduced cross-sectionalarea jointly curved fillets extending from the base top surface andterformed by said protuberances.

9. The method of manufacturing a blade preform from a blade blank havingan enlarged base portion, an airfoil section and transition regionsbetween the base portion and the airfoil section which comprisesapplying solely to a back surface of the base portion of the preformopposite the airfoil section a force P to move the preform along ametal-forming path, developing from said force P opposing forces Rrespectively directed angularly toward a transition region of the bladeblank lying between the base portion and the airfoil section thereof,said opposing forces being respectively directed toward said transitionregion of an angle a from a line normal to the direction of theapplication of the force P, said angle decreasing with movement of saidblade blank along said metal-forming path, and concurrently increasingthe force P to move said blade blank along said path while increasingthe force R in proportion to the quotient of the force P divided by thesine of said angle oz, said forces R being applied to said transitionregion through die members, thereby to reshape opposite faces of saidtransition region into generally concave fillets.

10. The method of claim 9 in which said angle a is decreased from asmall angle to a smaller angle during said reshaping of said oppositefaces, and in which said faces terminate in a region of the airfoilsection in which the cross-sectional area has been substantially reducedby said die members.

11. The method of claim 9 in which said angle a is,

id decreased from a starting angle to a finishing angle which fixes thelength of said metal-forming path, said die members having protuberanceswhich first form fillets and then reduce the cross-sectional area in theregion adjacent said fillets by an amount related to the extent ofchange of said angle.

12. The method of claim 9 in which said angle a is decreased from astarting angle to a finishing angle which fixes the length of saidmetal-forming path, said die members having protuberances which duringdecrease of said angles are moved toward each other and against saidtransition region first to form fillets and thereafter to reduce thecross-sectional area of the airfoil section in juxtaposition with thefillets, and abruptly arresting the movement of said blade blank topredetermine the extent of the reduction in said cross-sectional area.

13. In a method of manufacturing a rolled blade preform from a bladepreform having a base portion and an airfoil section interconnected bysmoothly curved generally concave fillets and with a region of reducedcrosssection in the region adjoining said fillets, the base por tionhaving a top surface adjacent said fillets, the steps which compriserelatively moving two dies, one toward the other to bring roundedcorners thereof into said region of reduced cross-sectional area,seating said preform into said dies by applying to the base of saidblade preform opposite the airfoil section a force which presses saidtop surface of said base against opposing shouldersurfaces of said dies,said dies having arcuate rolling surfaces, and rotating said dies indirections to reduce outwardly from said base the cross-sectional areaof said airfoil section with concurrent reversal of said applied forceto said base to place said airfoil section under substantial tensionduring said rolling thereof.

14. The method of claim 13 in which said dies after forced seating oftheir rounded corners against the fillets of said blade preform reshapethe fillets prior to reversal of the force applied to said base.

15. The method of claim 13 in which said reversed force is applied tosaid airfoil section in a direction parallel to a tangent to thatportion of the curved surface of the die engaging said airfoil section,the first of said dies being stationary, and the second of said diesbeing movable toward the stationary die along an arcuate path having itsaxis of rotation located in spaced relation from the line of action ofsaid tensional force in the direction of said stationary die.

16. The method of claim 13 in which said relative movement of said twodies, one toward the other, is along an arcuate path and ischaracterized by the fact that the angle between a tangent to thearcuate path and a center line formed by a trace of the centralairfoil-rolling plane between said arcuate rolling surfaces is less than17. Apparatus for manufacturing from a blade blank having an enlargedbase portion from which there extends angularly disposed transitionregions merging into a centrally disposed extension from which there isto be produced an airfoil section, comprising supporting structure, apair of dies havingrecesses in the die top surfaces extending onlypartially through the die, each recess defined by sides and a bottom,for receiving said base portion and also having adjacent the bottoms ofsaid recesses opposed convex protuberances whose radial axes aretransverse to the metal forming path of travel and disposed to engagesaid angular transition regions for suport of said preform, a pair ofdie-actuating levers supporting said dies with said protuberances facingeach other and engaging said transition regions, said levers at therespective ends remote from said protuberances being pivotally connectedto said supporting structure and extending angularly toward each otherto form with a travel line interconnecting their pivot point arelatively small angle which decreases as said dies are moved throughsaid metal-forming path, force-applying means adapted to engage the backsurface of said preform opposite the centrally disposed extension forapplying thereto a metalshaping force of increasing magnitude to locksaid preform into position between it and said protuberances and fordeveloping reaction forces from said levers angularly applied to saidtransition regions, said force applied solely to said back surface bythe positive mechanical connection formed by said preform producingrotation of said levers for rapid increase of said reaction forces assaid angle decreases to displace metal from said transition regionsoutwardly and inwardly thereof to lengthen said extension and to reducethe cross-sectional area of that extension in the region adjacent saidtransition regions, said rounded protuberances forming filletsconnecting said region of decreased cross-sectional area and said baseportion, said outward flow of metal from said transition regions fillingsaid recess as said levers move to their final positions with said angledecreased to zero.

18. The combination of claim 17 in which stop means are provided forsaid members in their final positions for reducing to zero said reactionforces and for applying metal-upsetting forces to said base.

19. The apparatus of claim 17 in which said suporting structure is madeof steel and which as a result of forces outwardly directed from saidpivoted ends of said levers as said angle approaches zero enlongatesrapidly to reduce the magnitude of said reaction forces applied to saidtransition regions, thereby limiting the maximum values which may bedeveloped by said forces during the reshaping of said transitionregions.

20. An apparatus for producing a blade preform from a blade blank whichin a transition region joining a base portion and an airfoil sectionthereof has a cross-sectional area which gradually increases from thecross-sectional area of said airfoil section to that of said baseportion, comprising a support, a pair of dies, a pair of dieactuatinglevers pivoted to said support at their remote ends and respectivelysupporting said dies in opposed relation to receive therebetween saidblade blank, said dies being spaced away from said support so that uponrotation of said levers toward said support said dies move toward eachother, and actuating means adapted to engage only said base portion ofsaid blade blank to move it downwardly and concurrently to rotate saidlevers toward said support to move said dies toward each other, saiddies having die top surfaces and recesses in the die top surfacesextending only partially through the dies, each recess defined by sidesand a bottom for receiving said base portion and also having adjacentthe bottom of said recesses outwardly protruding convex curved surfaceswhose radial axes are transverse to the metal forming path of travelengaging and supporting said blade blank from said transition region toform smoothly curved fillets therefrom and to reduce the cross-sectionof a portion of said airfoil section during continued rotation of saidlevers toward said support.

21. An apparatus for producing a blade preform from a blade blank whichin a transition region joining a base portion and an airfoil sectionthereof has a cross-sectional area which gradually increases from thecross-sectional area of the airfoil section to that of said baseportion, comprising a support, a pair of dies having die top surfacesand recesses in the die top surfaces extending only partially throughthe dies, each recess defined by sides and a bottom for receiving saidbase portion and also having adjacent the bottom of said recesses convexprotuberances whose radial axes are transverse to the metal forming pathof travel, a pair of die-actuating levers supporting said dies with saidprotuberances facing each other, said levers at the ends remote fromsaid protuberances being pivotally connected to said support andextending angularly toward each other with a separation distance betweensaid protuberances for support by said protuberances of the blade blankfrom an intermediate portion of said transition region, and meansadapted to apply alone to said base portion a force for rotating saidlevers in directions to decrease said separation distance and to developreaction forces angularly directed toward said transition region, saidforce applied to said base portion being of a magnitude to shape themetal of said transition region into fillets corresponding in shape withsaid convex protuberances and concurrently to reduce the cross-sectionalarea of said airfoil section substantially below its initialcross-sectional area.

22. The apparatus of claim 21 in which said means for applying saidforce to said base portion includes a reciprocable member having arecess to receive therewithin said base portion.

23. The apparatus of claim 21 in which said support is made of steelwhich elongates within its elastic limit to regulate the maximummagnitudes of said reaction forces.

24. Apparatus for producing a blade preform from a blade blank which hasa base portion and a portion depending therefrom to form an airfoilsection, comprising a support, a pair of dies having die top surfacesand recesses in the die top surfaces extending only partially throughthe dies, each recess defined by sides and a bottom for receiving saidbase portion and also having adjacent the bottom of said recesses convexprotuberances whose radial axes are transverse to the metal forming pathof travel, a pair of die-actuating levers supporting said dies with saidprotuberances facing each other, said levers at the ends remote fromsaid protuberances being pivotally connected to said support andextending angularly toward each other with a separation distance betweensaid protuberances to receive therebetween said depending section,biasing means for biasing said levers to position where said separationdistance is adequate for reception between said protuberances of saidairfoil section, stop members for limiting rotation of said levers indirections to decrease said separation distance to predetermine saidseparation distance upon movement of said levers between an initialposition and a final position, and means adapted to apply alone to saidbase portion a force for rotating said levers in said directions todecrease said separation distance for developing reaction forces forshaping a selected portion of said blade blank, said biasing means beingeffective upon removal of said force applied to said base portion toreturn said levers to their initial positions.

25. The apparatus of claim 24 in which an ejector is provided to engagethe end portion of the airfoil section remote from said base portion,and resilient means for said ejector compressed upon movement of saidblade blank toward said base and cooperating with said biasing means forsaid levers in moving them from their initial positions to their finalpositions and for releasing from said dies the blade preform.

26. In a method for manufacturing a blade from a blade blank having atleast one base, an airfoil and a fillet area between a base top surfaceand the airfoil, the steps of: (1) reshaping the blade blank bypartially forming the base top surface, and then forming the base topsurface, the fillet area and a part of the airfoil adjacent the filletarea simultaneously so that the fillet area and the part of the airfoiladjacent the fillet area are smaller in cross-section than the airfoil,the radius of the fillet area being greater than the radius of a portionof the rollforming dies used subsequently to mate with the fillet areaof the blade blank prior to roll-forming; (2) further reshaping andrestraining the blade blank between the portion of the roll-forming diesprior to roll-forming motion of the dies by forcing the dies into thereshaped fillet area with a force at least equal to that required topermanently deform material of the blade blank and simultaneouslyforcing the base top surface and fillet area against the dies with aforce less than that required to permanently deform the material of theblade blank, the reshaped fillet area being further reshaped by theportion of the dies forced into the fillet area; (3) and thenroll-forming the

1. THE METHOD OF MANUFACTURING A BLADE PREFORM FROM A BLADE BLANK HAVINGAN ENLARGED BASE PORTION AND A CENTRALLY DISPOSED EXTENSION OFMATERIALLY SMALLER CROSSSECTIONAL AREA AND INCLUDING ANGULAR TRANSITIONREGIONS BETWEEN THE BASE PORTION AND SAID EXTENSION, WHICH COMPRISESSUSPENDING FROM SAID TRANSITION REGIONS SAID PREFORM BY ROUNDED CONVEXSURFACES OF OPPOSED DIES, APPLYING SOLELY TO THE BACK SURFACE OF SAIDBASE PORTION OPPOSITE THE CENTRALLY DISPOSED EXTENSION A FORCE TO MOVESAID PREFORM ALONG A METAL-FORMING PATH EXTENDING INTERMEDIATE SAIDDIES, DEVELOPING FROM FORCE OPPOSING FORCES RESPECTIVELY DIRECTEDANGULARLY TOWARD SAID TRANSITION REGIONS OF SAID BLADE BLANK THEREBY TOMAINTAIN SAID PREFORM IN POSITION FOR CONTINUED ENGAGEMENT BY SAIDROUNDED SURFACES OF SAID DIES DURING ITS MOVEMENT ALONG SAIDMETAL-FORMING PATH, INCREASING SAID FORCE APPLIED TO SAID BACK SURFACETO METAL-MOVING MAGNITUDES, AND CONCURRENTLY INCREASING SAID ANGULARLYDIRECTED OPPOSING FORCES IN PROPORTION TO THE QUOTIENT OF SAID FORCEAPPLIED TO SAID BACK SURFACE DIVIDED BY THE SINE OF THE ANGLE BETWEEN ALINE NORMAL TO THE DIRECTION OF THAT APPLIED FORCE AND THE ANGULARDIRECTION OF EACH OF SAID OPPOSING FORCES, SAID ANGLE DECREASING AS SAIDPREFORM MOVES THROUGH SAID METAL-FORMING PATH, SAID APPLIED FORCE ANDSAID ANGULARLY DIRECTED FORCES OF INCREASING MAGNITUDE MOVING METAL INDIVIDED FLOW SAID TRANSITION REGIONS, SOME OUTWARDLY AND SOME INWARDLY,RELATIVE TO SAID EXTENSION TO FORM ROUNDED CONCAVE FILLETS FROM SAIDTRANSITION REGIONS WITH CONCURRENT REDUCTION IN THE CROSS-SECTIONAL AREAOF SAID EXTENSION ADJACENT TO SAID FILLETS AND WITH CONCURRENT INCREASEIN THE LENGTH OF SAID EXTENSION.